CN113683439B - Shell, preparation method thereof and electronic equipment - Google Patents

Abstract

The present application provides a method for preparing a shell, comprising: coating and/or soaking a polymer ceramic body in a pretreatment liquid, and after drying, a pretreatment layer is formed on the surface of the polymer ceramic body to obtain a composite body body, wherein the polymer ceramic body includes a polymer, and the pretreatment liquid includes an accelerator capable of promoting the cross-linking of the polymer; after the composite body is heat-treated and hot-pressed, the pretreatment The layer is treated to obtain a polymer ceramic layer, and a shell is produced. After the polymer ceramic body is treated with the pretreatment liquid, a pretreatment layer is formed on its surface, so that in the subsequent heat treatment process, the degree of crosslinking of the polymer in the polymer ceramic body can be improved, and the heat treatment time can be greatly reduced. , thereby improving the mechanical properties of the casing and reducing the preparation time of the casing. The present application also provides a housing and an electronic device.

Description

Shell and its preparation method and electronic equipment

technical field

The application belongs to the technical field of electronic products, and in particular relates to a casing, a preparation method thereof, and electronic equipment.

Background technique

With the improvement of consumption level, consumers not only pursue the diversification of functions of electronic products, but also have higher and higher requirements for their appearance and texture. In recent years, ceramic materials have become a hot spot in the research of electronic equipment casings due to their warm and moist texture. In the related art, products are prepared by composite materials formed of resin and ceramic materials, but the production cycle of the current products is long, and at the same time, compared with real ceramic products, there is still a gap in its strength. Therefore, the current ceramic shell and its preparation method still need to be improved.

Contents of the invention

In view of this, the present application provides a casing, a preparation method thereof, and an electronic device.

In the first aspect, the present application provides a method for preparing a shell, comprising: coating and/or soaking a polymer ceramic body with a pretreatment liquid, and forming a pretreatment layer on the surface of the polymer ceramic body after drying , to obtain a composite green body, wherein, the polymer ceramic green body includes a polymer, and the pretreatment liquid includes an accelerator capable of promoting the crosslinking of the polymer; after the composite green body is heat-treated and hot-pressed, then The pretreatment layer is removed to obtain a polymer ceramic layer to obtain a casing.

In a second aspect, the present application provides a casing manufactured by the preparation method described in the first aspect, the casing comprising a polymer ceramic layer.

In a third aspect, the present application provides an electronic device, including the casing described in the second aspect.

The application provides a shell and a method for preparing the shell. After the polymer ceramic body is treated with a pretreatment liquid, a pretreatment layer is formed on its surface, so that the polymer ceramic body can be improved in the subsequent heat treatment process. The degree of cross-linking of the polymer in the medium, while greatly reducing the time of heat treatment, thereby improving the mechanical properties of the shell while reducing the preparation time of the shell; the electronic device with the shell has excellent mechanical properties, and can better meet User needs.

Description of drawings

In order to more clearly describe the technical solutions in the embodiments of the present application, the following will describe the drawings that need to be used in the embodiments of the present application.

FIG. 1 is a flowchart of a method for preparing a housing provided in an embodiment of the present application.

Fig. 2 is a flowchart of a method for preparing a polymer ceramic green body provided by an embodiment of the present application.

Fig. 3 is a flowchart of a method for preparing a polymer ceramic green body provided in another embodiment of the present application.

FIG. 4 is a schematic structural diagram of a housing provided in an embodiment of the present application.

FIG. 5 is a schematic structural diagram of a housing provided in another embodiment of the present application.

FIG. 6 is a schematic structural diagram of an electronic device provided in an embodiment of the present application.

FIG. 7 is a schematic diagram of the structure and composition of an electronic device provided by an embodiment of the present application.

Detailed ways

The following are preferred embodiments of the application. It should be pointed out that for those skilled in the art, without departing from the principle of the application, some improvements and modifications can also be made, and these improvements and modifications are also considered as the present invention. The scope of protection applied for.

The following disclosure provides many different implementations or examples for implementing different structures of the present application. To simplify the disclosure of the present application, components and arrangements of specific examples are described below. Of course, they are examples only and are not intended to limit the application. Furthermore, the present application may repeat reference numerals and/or reference letters in various instances, such repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and/or arrangements discussed. In addition, the present application provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize the use of other processes and/or the use of other materials.

Please refer to Fig. 1, which is a flow chart of the preparation method of the housing provided in an embodiment of the present application, including:

S101: Coating and/or immersing the polymer ceramic body in a pretreatment liquid, and forming a pretreatment layer on the surface of the polymer ceramic body after drying to obtain a composite body, wherein the polymer ceramic body includes a polymer, and the pretreatment layer is formed on the surface of the polymer ceramic body. The treatment fluid includes an accelerator capable of promoting crosslinking of the polymer.

S102: After the composite green body is heat-treated and hot-pressed, the pre-treatment layer is removed to obtain a polymer ceramic layer to obtain a casing.

In this application, after the polymer ceramic body is treated with the pretreatment liquid, the accelerator in the pretreatment liquid can promote the crosslinking of the polymer in the polymer ceramic body during the heat treatment process, and at the same time greatly reduce the time of heat treatment , so as to not only improve the mechanical properties of the manufactured shell 100, but also greatly reduce the preparation time and improve the preparation efficiency. In related technologies, various materials such as glass, metal, plastic, and ceramics can be used in the electronic device 200. However, the dielectric loss of glass is high, and its use on millimeter waves has certain limitations, and its anti-drop performance needs to be improved; Metal will shield the product signal due to conductivity; the texture of plastic needs to be improved; ceramics have a high dielectric constant, which will seriously damage the signal. In this application, by setting the polymer ceramic layer 10, the high-grade texture of ceramics is retained, and the dielectric properties meet the requirements of millimeter waves, so as to meet the requirements of 5G communication technology. At the same time, the inventors of the present application found that the surface hardness of the polymer ceramic layer 10 is low, the scratch resistance is poor, the product strength is not enough, and a thinner thickness cannot be realized, and the overall processing time is long, and the production efficiency is low; therefore, the present invention The inventor of the application coats and/or soaks the pre-treatment liquid on the polymer ceramic body, so that during the heat treatment, the accelerator in the pre-treatment liquid can promote the crosslinking of the polymer in the polymer ceramic body and improve the performance of the polymer. The degree of cross-linking can also greatly reduce the length of heat treatment, improve production efficiency, and increase the hardness of the shell 100, improve the ability to resist scratches, and is more conducive to its application.

In S101, a composite body is obtained by coating and/or immersing the polymer ceramic body in a pretreatment liquid, and forming a pretreatment layer on the surface of the polymer ceramic body after drying. Through the pretreatment, a pretreatment layer is formed on the surface of the polymer ceramic body, the polymer ceramic body includes a polymer, and there is an accelerator that can promote the crosslinking of the polymer in the pretreatment layer, so that the subsequent heat treatment process can Promote the cross-linking of polymers and increase the degree of cross-linking.

Please refer to FIG. 2 , which is a flow chart of a method for preparing a polymer ceramic green body provided in an embodiment of the present application, including:

S1011: After the ceramic particles are mixed with the polymer, the injection molding feed is obtained by granulation.

S1012: The injection molding feed is injected to obtain a polymer ceramic green body.

In S1011, the injection molding feed is formed by mixing and granulating the ceramic particles and the polymer, which facilitates subsequent injection molding.

In the embodiment of the present application, the ceramic particles include at least one of zinc oxide, zirconium oxide, aluminum oxide, silicon dioxide, titanium oxide and silicon carbide. The above-mentioned ceramic particles are resistant to high temperature, corrosion, high in hardness and good in strength, which is beneficial for improving the performance of the housing 100 . In one embodiment, the refractive index of the ceramic particles is greater than 2, which is beneficial to further enhance the ceramic texture of the casing 100 . In the embodiment of the present application, the diameter of the ceramic particles is 20 nm-1 μm. Selecting the ceramic particles with the above size is beneficial to mixing with the polymer, and at the same time, it is beneficial to increase the ceramic phase content of the housing 100 . Further, the diameter of the ceramic particles is 100nm-800nm. Furthermore, the diameter of the ceramic particles is 300nm-600nm. Specifically, the diameter of the ceramic particles may be, but not limited to, 50nm, 100nm, 250nm, 400nm, 500nm, 650nm, 700nm, 800nm, 900nm or 1 μm. It can be understood that the morphology of the ceramic particles can be, but not limited to, a sphere, a spheroid, and the like.

In the present application, by mixing the ceramic particles with the polymer, it is beneficial to reduce the mass of the housing 100 while improving the toughness of the housing 100 . In the embodiment of the present application, the polymer includes a thermoplastic resin, and the thermoplastic resin includes at least one of polyphenylene sulfide, polyphenylene sulfone, polyamide, and ethylene-vinyl acetate copolymer. The physical and chemical properties of the above-mentioned thermal polymer can match the manufacturing process of the housing 100 , and will not decompose during the manufacturing process, and will not increase the difficulty of the manufacturing process, which is beneficial to reduce production costs.

It can be understood that when the ceramic particles and the polymer are mixed, the mixing ratio of the ceramic particles and the polymer can be selected according to the content of each substance in the polymer ceramic layer 10 , which is not limited. In one embodiment, the mass ratio of the ceramic particles to the polymer is (0.5-0.8):(0.2-0.5), which is conducive to preparing the polymer ceramic layer 10 with high hardness, good strength and strong ceramic texture. In a specific embodiment, the mass content of 50%-80% of the ceramic particles is mixed with 20%-50% of the polymer to form a mixture.

In the embodiment of the present application, mixing includes at least one of blending and banburying. Specifically, mixing can be carried out in at least one of a blending extruder and an internal mixer, so that the substances in the mixture are uniformly dispersed. In one embodiment, the mixture is blended and/or banburyed for 2-5 times, and the duration of one blending or banburying is 1h-2h. Specifically, the temperature of blending or banburying is 300°C-350°C. In this application, injection molding feed can be obtained by granulating the mixed material. In one embodiment, the ceramic particles and the polymer can be mixed, placed in an integrated mixing and granulating machine, and the injection molding feed can be obtained after mixing and granulating. Specifically, the temperature of banburying and granulation can be but not limited to 200°C-350°C, and the time of banburying and granulation can be but not limited to 1h-12h. Furthermore, the banburying process is in a negative pressure state, and the absolute value of the pressure is less than 0.01MPa, so as to effectively prevent the polymer from being oxidized, and can effectively promote the elimination of gases generated by side reactions.

In S1012, the technical parameters of injection molding can be selected according to the properties of the selected polymer. In one embodiment of the present application, drying the injection molding feedstock is also included before injection molding. In one embodiment, the drying treatment includes drying at 90°C-150°C for 8h-12h. Drying process to remove moisture from injection molding feedstock. In one embodiment of the present application, when the polymer includes at least one of polyphenylene sulfide, polyphenylene sulfone, polyamide and ethylene-vinyl acetate copolymer, the injection molding temperature is 320°C-360°C, and the injection The speed is 70%-100%, the injection pressure is 120MPa-250MPa; the mold temperature is 130°C-180°C, and the holding time is 2s-60s to obtain a polymer ceramic green body. Further, the molding temperature of injection molding is 320°C-340°C, the injection speed is 70%-90%, the injection pressure is 150MPa-200MPa; the mold temperature is 140°C-170°C, and the holding time is 5s-50s to obtain the polymer Ceramic bodies. By adopting the above-mentioned conditions for injection molding, a polymer ceramic green body with good molding effect and high molding yield can be obtained. The shape of the polymer ceramic body obtained by injection molding can be selected as needed, and the thickness of the polymer ceramic body can also be selected according to needs. It can be understood that other molding methods such as tape casting can also be used to prepare the polymer ceramic green body. In this application, the method of injection molding is simpler to operate, and compared with tape casting, there is no need to consider the compatibility problem between the solvent and the polymer phase, and the preparation cost is low.

Please refer to FIG. 3 , which is a flowchart of a method for preparing a polymer ceramic green body provided in another embodiment of the present application, including:

S2010: After the ceramic particles are pretreated, processed ceramic particles are obtained.

S2011: After the treated ceramic particles are mixed with the polymer, the injection molding feed is obtained by granulation.

S2012: The injection molding feed is injected to obtain a polymer ceramic green body.

In S1011, the injection molding feed is formed by mixing and granulating the ceramic particles and the polymer, which facilitates subsequent injection molding.

It can be understood that, for detailed descriptions of S2011 and S2012, refer to the descriptions of the corresponding parts of S1011 and S1012 in the foregoing implementation manners, and details are not repeated here.

In one embodiment of the present application, after the pretreatment of the ceramic particles, obtaining the processed ceramic particles includes: performing modification treatment on the ceramic particles, and obtaining the processed ceramic particles after spray granulation. By modifying the ceramic particles, the compatibility between the ceramic particles and the polymer is improved, thereby improving the performance of the housing 100 .

In an embodiment of the present application, the ceramic particles are modified by mixing the ceramic particles with a modifier. Optionally, the modifying agent includes at least one of silane coupling agent, ammonium citrate, polyacrylic acid, ammonium polymethacrylate and triethanolammonium. In this application, the modifier can be selected according to the properties of the polymer. In another embodiment of the present application, when the ceramic particles are mixed with the modifier, the ceramic particles are 60-98 parts by weight, and the modifier is 0.1-3 parts. The above mixing ratio can completely modify the ceramic particles without agglomerating the modifying agent. Further, when the ceramic particles are mixed with the modifying agent, by weight fraction, the ceramic particle is 60-80 parts, and the modifying agent is 0.5-2 parts. In yet another embodiment of the present application, when the ceramic particles are mixed with the modifier, a dispersing aid is also added, so that the ceramic particles can be better uniformly dispersed. Specifically, in terms of parts by weight, when mixing, the amount of ceramic particles is 60-98 parts, the modifier is 0.1-3 parts, and the dispersion aid is 0.1-1 part. In yet another embodiment of the present application, when the ceramic particles are mixed with the modifying agent, a coloring agent is also added, so that the appearance color of the polymer ceramic body can be improved. Specifically, in terms of parts by weight, when mixing, the ceramic particle is 60-98 parts, the modifier is 0.1-3 parts, and the coloring agent is 1-20 parts. In the present application, the colorant includes at least one of an organic colorant and an inorganic colorant, and the colorant can be selected according to the desired color, for example, the colorant can be selected from cobalt oxide or carbon black, etc., so that the polymer ceramic body Appearing black, and for example, the coloring agent can be, but not limited to, at least one selected from iron oxide, cerium oxide, nickel oxide, bismuth oxide, zinc oxide, manganese oxide, chromium oxide, copper oxide, vanadium oxide, and tin oxide. In yet another embodiment of the present application, when the ceramic particles are mixed with the modifier, a dispersant and a colorant are also added, the ceramic particles are 60-98 parts, the modifier is 0.1-3 parts, and the dispersion aid is 0.1-1 part, coloring agent is 1-20 parts.

In another embodiment of the present application, the ceramic particles are mixed with the modifier to obtain a mixed material, and the mixed material is ball milled to obtain a mixed slurry. It can be understood that when a dispersant and/or a colorant is added, a mixed material is obtained after all materials are mixed, and the mixed material is then ball milled. Optionally, ball milling includes mixing the mixed material, water and ball milling beads, and ball milling for 12h-48h, so as to completely modify the ceramic particles. In one embodiment, the mass ratio of the mixed material, water and ball milling beads is 1:(1-3):(0.5-1), which is beneficial to the thorough mixing of the mixed material and the modification of the ceramic particles. Specifically, the mass ratio of the mixed material, water and ball milling beads can be, but not limited to, 1:1:1, 1:2:1, 1:3:1, 1:1.5:0.5, 1:2:0.5, 1:2 :0.8 or 1:2.5:1 etc. In the present application, ball milling can be performed at room temperature, such as 15°C-35°C and the like.

In yet another embodiment of the present application, the mixed slurry is spray-granulated to obtain treated ceramic particles. Specifically, the temperature of the spray granulation can be selected according to the temperature of the solvent in the mixed slurry, and the spray granulation can be performed in a spray granulator. In one embodiment, during the spray granulation process, the feed temperature is 70-80°C, the inlet air temperature is 130-160°C, the exhaust air temperature is 70-85°C, the temperature in the tower is 70-90°C, and the negative pressure in the tower is The pressure is 50pa-150pa. Through the above process, treated ceramic particles with uniform size can be formed, which is beneficial for mixing with polymers. Specifically, after spray granulation, the diameter of the treated ceramic particles is 100 nm-1 μm.

In the embodiment of the present application, the polymer ceramic body includes polymer and ceramic particles. Further, the ceramic particles are evenly dispersed in the polymer ceramic body.

In S101, the pretreatment liquid includes an accelerator capable of accelerating polymer crosslinking. In the embodiment of the present application, the accelerator includes at least one of an organic accelerator and a metal accelerator, so as to accelerate the cross-linking of the polymer. In one embodiment, the organic accelerator includes at least one of amines, phenols, benzenes and ethers. Specifically, the organic accelerator includes at least one of melamine, hexamethoxymethyl melamine, trihydroxybenzene, pentaerythritol triallyl ether, phenol and hindered phenols. In another embodiment, the metal promoter includes at least one of silver, copper, iron, lead, zinc, and magnesium. In the present application, the pretreatment liquid may contain only organic accelerators or metal accelerators; it may also include both organic accelerators and metal accelerators. The inventors of the present application found that adding an organic accelerator and a metal accelerator at the same time can further increase the crosslinking speed, achieve a higher level of crosslinking within the same time, and further reduce the processing time and shorten the preparation time. In one embodiment, the mass ratio of the organic accelerator to the metal accelerator in the accelerator is 1.2-4, which is conducive to the rapid improvement of the crosslinking degree of the polymer in the subsequent heat treatment. Further, the mass ratio of the organic accelerator and the metal accelerator in the accelerator is 1.5-3.5. Specifically, the mass ratio of the organic accelerator to the metal accelerator in the accelerator may be, but not limited to, 1.5, 2, 2.5, 2.8, 3, 3.4 or 3.5. In a specific embodiment, melamine and zinc may be mixed in a mass ratio of 1.2-4 as an accelerator. In another embodiment of the present application, the mass content of the accelerator in the pretreatment is 10%-50%. The accelerator in the above content can effectively promote the crosslinking of the polymer in the subsequent treatment process, and can be well dispersed in the pretreatment liquid at the same time. Further, the mass content of the accelerator in the pretreatment is 15%-45%. Furthermore, the mass content of the accelerator in the pretreatment is 20%-40%. Specifically, the mass content of the accelerator in the pretreatment may be, but not limited to, 15%, 18%, 22%, 25%, 27%, 30%, 35%, 40% or 43%.

In one embodiment of the present application, the pretreatment liquid includes a solvent. In one embodiment, the mass content of the solvent in the pretreatment liquid is 50%-80%. Further, the mass content of the solvent in the pretreatment liquid is 60%-80%. Furthermore, the mass content of the solvent in the pretreatment liquid is 65%-75%. Specifically, the mass content of the solvent in the pretreatment may be, but not limited to, 52%, 55%, 57%, 60%, 63%, 65%, 70%, 76% or 79%. In the present application, the solvent includes at least one of water, ethanol and acetone. In another embodiment of the present application, the pretreatment liquid includes a dispersant. The degree of uniform dispersion of the accelerator can be improved by adding a dispersant. In one embodiment, the mass content of the dispersant in the pretreatment liquid is 0.5%-5%. Further, the mass content of the dispersant in the pretreatment liquid is 1%-3.5%. Specifically, the mass content of the dispersant in the pretreatment may be, but not limited to, 0.5%, 1%, 1.8%, 2%, 2.5%, 3%, 3.7%, 4% or 4.5%. In another embodiment, the dispersant includes at least one of silane coupling agent, stearic acid, ammonium stearate and polyethylene glycol. In yet another embodiment of the present application, the pretreatment liquid includes a binder. The accelerator is attached to the surface of the polymer ceramic body after spraying and soaking by adding a binder. In one embodiment, the mass content of the binder in the pretreatment liquid is 1%-5%. Further, the mass content of the binder in the pretreatment liquid is 1.5%-4%. Furthermore, the mass content of the binder in the pretreatment liquid is 2%-3.5%. Specifically, the mass content of the binder in the pretreatment may be, but not limited to, 1%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 4.7%. In another embodiment, the binder includes at least one of polyvinyl alcohol, polyvinyl butyral, polyethylene glycol, and acrylic resin. In a specific embodiment, the pretreatment liquid includes accelerators, dispersants, binders and solvents. Further, the mass content of the accelerator in the pretreatment liquid is 10%-50%, the mass content of the dispersant is 0.5%-5%, the mass content of the binder is 1%-5%, and the mass content of the solvent is The mass content is 50%-80%, so that the homogeneous dispersion of the accelerator can be ensured, and the accelerator can be attached to the surface of the polymer ceramic body after processing the polymer ceramic body.

In this application, the pretreatment liquid can be coated on the surface of the polymer ceramic body by coating, and the polymer ceramic body can also be soaked in the pretreatment liquid, so that the polymer ceramic body can be dried after drying. A pretreatment layer is formed on the surface of the ceramic body. In the embodiment of the present application, the coating and/or immersion includes treatment at 15° C.-40° C. for 1 h-2 h, so that the pre-treatment liquid can better and uniformly adhere to the polymer ceramic body. Further, the coating and/or soaking includes treating at 20°C-35°C for 1h-2h. In the embodiment of the present application, drying includes processing at 80°C-100°C. Further, drying includes processing at 85°C-100°C. Specifically, the drying time can be selected according to the volatilization of the solvent.

In the embodiment of the present application, the thickness of the pretreatment layer is 10 μm-100 μm. Specifically, the thickness of the pretreatment layer may be, but not limited to, 10 μm, 20 μm, 40 μm, 50 μm, 70 μm, 85 μm or 100 μm. Setting the pre-treatment layer with the above-mentioned thickness can promote the cross-linking of the polymer in the subsequent heat treatment process without waste. In this application, the composite body is a polymer ceramic body and a pretreatment layer arranged on the surface of the polymer ceramic body. It can be understood that the pretreatment layer can be located on one or more surfaces of the polymer ceramic body, or on all surfaces of the polymer ceramic body, and can be selected according to needs.

In S102, the polymer in the polymer ceramic body is cross-linked by heat treatment, and at the same time, under the action of the accelerator, the degree of cross-linking of the polymer is accelerated to reduce the time of heat treatment; and the internal pores are eliminated after hot pressing , improve the density; further remove the pre-treatment layer to obtain the polymer ceramic layer 10, and manufacture the shell 100.

In the embodiment of the present application, the heat treatment time is less than or equal to 12 hours. Further, the heat treatment time is less than or equal to 8 hours. Further, the heat treatment time is less than or equal to 5h. In related technologies, heat treatment is used to increase the degree of crosslinking of polymers, and the heat treatment time is 48h-72h, which greatly increases the preparation time and reduces production efficiency. The inventors of the present application found that by setting a pretreatment layer on the surface of the polymer ceramic body, the accelerator reacts with the polymer during the heat treatment process, which further promotes the crosslinking of the polymer on the basis of the original polymer crosslinking. , so as to improve the overall degree of crosslinking; compared with the polymer ceramic body without pretreatment liquid treatment, the polymer ceramic layer 10 made of the composite body has a higher degree of crosslinking, high surface hardness, and scratch resistance The wounding effect is good, the overall strength is good, and the time of heat treatment is greatly shortened, and the time of heat treatment is less than or equal to 12h.

In an embodiment of the present application, the heat treatment temperature is higher than the melting temperature of the polymer and lower than the decomposition temperature of the polymer. In another embodiment of the present application, the heat treatment includes raising the temperature from 15°C-40°C to 220°C-280°C within 0.5h-1h, then keeping it warm for 0.5h-2h, and then changing the temperature from 220°C-280°C within 0.5h-1h After heating up to 300°C-380°C, keep it warm for 0.5h-4h. By adopting the above-mentioned segmented heat treatment process, the composite green body can be heated evenly, and the degree of crosslinking of the polymer can be uniform. In the first stage, the polymer in the polymer ceramic body is pre-softened, and the accelerator in the pretreatment layer can penetrate into the polymer ceramic body and react with the polymer; in the second stage, the temperature rises, and the polymer Further cross-linking occurs between them, thereby improving the surface hardness and overall strength of the housing 100 . In one embodiment, when the heat treatment is performed between the polymer ceramic bodies, the heat treatment includes raising the temperature from 15°C-40°C to 220°C-280°C within 0.5h-1h and then keeping it warm for 24h, and then within 0.5h-1h After heating from 220°C-280°C to 300°C-380°C, keep it warm for 24 hours, which is much longer than the above-mentioned heat treatment time. In a specific embodiment, when the polymer includes at least one of polyphenylene sulfide, polyphenylene sulfone, polyamide and ethylene-vinyl acetate copolymer, the above-mentioned heat treatment process can be used to greatly reduce the length of heat treatment, And the degree of cross-linking of the polymer increases.

In the present application, the internal compactness is improved by hot pressing, the internal microscopic defects are reduced, and the strength of the casing 100 is improved. In the embodiment of the present application, the temperature of the hot pressing is higher than the glass transition temperature of the polymer and lower than the decomposition temperature of the polymer. Further, the temperature of hot pressing is 20°C-60°C higher than the glass transition temperature of the polymer. Within this range, the polymer is in a highly elastic state, and the molecular chains can move, making them closer to the ceramic particles under pressure, improving the performance of the housing 100 . In an embodiment of the present application, the hot pressing includes processing at 20MPa-80MPa and 300°C-400°C for 2h-12h. The above-mentioned hot pressing process can enhance the compactness inside the polymer ceramic layer 10 and further enhance the strength of the casing 100 . Further, hot pressing includes processing at 30MPa-70MPa and 310°C-460°C for 3h-10h. Specifically, the pressure of hot pressing can be but not limited to 28MPa, 35MPa, 40MPa, 45MPa, 50MPa, 60MPa or 75MPa, etc. The temperature of hot pressing can be but not limited to 310°C, 320°C, 340°C, 350°C, 360°C Or 380°C, etc., the hot pressing time can be but not limited to 2h, 4h, 5h, 7h, 10h or 11h, etc. In another embodiment of the present application, when the polymer includes at least one of polyphenylene sulfide, polyphenylene sulfone, polyamide and ethylene-vinyl acetate copolymer, the above hot pressing process can be used. Specifically, the hot pressing can be performed, but not limited to, in a hot pressing sintering furnace, and the whole process is performed under an inert atmosphere, such as nitrogen or argon, etc. can be introduced. In this application, after hot pressing, the polymer ceramic layer 10 can be removed after natural cooling.

In this application, after hot pressing, the pre-treatment layer is also removed, so that the polymer ceramic layer 10 with high surface hardness and good strength can be obtained. In the embodiment of the present application, the pre-treatment layer is removed by at least one of computer numerical control precision machining (CNC machining) and grinding and polishing. The pre-treatment layer can be removed by CNC processing, and the polymer ceramic layer 10 with the final size required for assembly can be obtained; for example, the polymer ceramic layer 10 can be made smoother by CNC processing. The process conditions of CNC machining can be selected according to needs. In a specific embodiment, the hot-pressed polymer ceramic body is CNC processed according to the desired shape, and the CNC processing uses a polycrystalline diamond (PCD) milling cutter, the spindle speed is 10000rpm-25000rpm, and the single cutting amount is 10μm -500 μm. Grinding and polishing can not only remove the pretreatment layer, but also reduce the surface roughness of the polymer ceramic layer 10 . In this application, five-axis grinding and polishing machines, 13.6B double-sided grinding machines or sweeping machines can be used for processing. In one embodiment, abrasive polishing includes rough polishing and fine polishing. Specifically, at least one of a sweeping machine, a double-sided grinding machine, and a five-axis polishing machine can be used for rough polishing, and the polishing disc is selected from pig hair, dermabrasion disc, damping cloth, rubber wire, copper wire, carpet or pig hair Cooperate with one or more of the skin grinding composite materials, the rough polishing liquid includes at least one of water-based diamond polishing liquid and oil-based diamond polishing liquid, the particle size of diamond micropowder in the rough polishing liquid is 0.5 μm-20 μm, coarse The concentration of the polishing liquid is 1wt%-30wt%; fine polishing can be selected from at least one of a sweeping machine and a double-sided grinding machine, and the fine polishing liquid includes at least one of silicon oxide polishing liquid and cerium oxide polishing liquid. The grain size of the particles in the polishing liquid is 50nm-500nm, and the concentration of the fine polishing liquid is 5wt%-45wt%. In a specific embodiment, CNC processing can be performed first, and then grinding and polishing can be performed, so that the pretreatment layer can be effectively removed, and the polymer ceramic layer 10 with a smooth surface can be obtained.

In the embodiment of the present application, the preparation method of the shell 100 also includes spraying or depositing a protective material on the surface of the polymer ceramic layer 10 to form the protective layer 20; specifically, the thickness of the protective layer 20 can be, but not limited to, 0.5 μm- 3μm, deposition can be, but not limited to, evaporation coating, sputtering, vacuum plating, etc. In one embodiment, an anti-fingerprint layer is formed by coating an anti-fingerprint agent on the surface of the polymer ceramic layer 10 to improve the anti-fingerprint effect of the casing 100 . In another embodiment, the hardened layer is formed by evaporating a hardened material on the surface of the polymer ceramic layer 10 . Specifically, the hardening material may include, but is not limited to, at least one of graphite, aluminum oxide, zirconium oxide, silicon oxide, chromium nitride, and titanium nitride.

The present application also provides a casing 100 manufactured by the preparation method described in any one of the above-mentioned embodiments, and the casing 100 includes a polymer ceramic layer 10 . Please refer to FIG. 4 , which is a schematic structural diagram of a casing 100 provided by an embodiment of the present application. The casing 100 includes a polymer ceramic layer 10 . The shell 100 provided by the present application has high surface hardness, good strength, and good ceramic texture, and has wide application prospects.

In the embodiment of the present application, the polymer ceramic layer 10 includes polymer and ceramic particles. In one embodiment, the polymer in the polymer ceramic layer 10 is cross-linked to form a three-dimensional network structure, and ceramic particles are dispersed in the three-dimensional network structure. In the embodiment of the present application, the polymer includes a thermoplastic resin, and the thermoplastic resin includes at least one of polyphenylene sulfide, polyphenylene sulfone, polyamide, and ethylene-vinyl acetate copolymer.

In the embodiment of the present application, the mass content of ceramic particles in the polymer ceramic layer 10 is greater than or equal to 40%. The higher content of ceramic particles in the polymer ceramic layer 10 can improve the surface hardness and enhance the texture of ceramics. Further, the mass content of ceramic particles in the polymer ceramic layer 10 is 40%-80%. Specifically, the mass content of ceramic particles in the polymer ceramic layer 10 may be, but not limited to, 40%, 45%, 50%, 58%, 60%, 65%, 72%, 75% or 80%. In the embodiment of the present application, the ceramic particles include at least one of zinc oxide, zirconium oxide, aluminum oxide, silicon dioxide, titanium oxide and silicon carbide. The above-mentioned ceramic particles are resistant to high temperature, corrosion, high in hardness and good in strength, which is beneficial for improving the performance of the housing 100 .

In this application, the hardness of the surface of the polymer ceramic layer 10 is detected under a pressure of 1 kg by adopting the GB/T 6739-1996 standard. In the embodiment of the present application, the pencil hardness of the surface of the polymer ceramic layer 10 is greater than or equal to 3H. Further, the pencil hardness of the surface of the polymer ceramic layer 10 is 3H-7H, thereby greatly improving the hardness and strength of the casing 100 . Furthermore, the pencil hardness of the surface of the polymer ceramic layer 10 is 4H-7H. Specifically, the pencil hardness of the surface of the polymer ceramic layer 10 may be, but not limited to, 3H, 4H, 5H, 6H or 7H.

In the present application, the Vickers hardness of the polymer ceramic layer 10 is detected under a pressure of 1 kg by adopting GB/T 16534-2009 standard. In the embodiment of the present application, the Vickers hardness of the polymer ceramic layer 10 is greater than or equal to 400HV. Further, the Vickers hardness of the polymer ceramic layer 10 is 400HV-800HV. Furthermore, the Vickers hardness of the polymer ceramic layer 10 is 500HV-700HV. Specifically, the Vickers hardness of the polymer ceramic layer 10 may be, but not limited to, 400HV, 450HV, 500HV, 550HV, 600HV, 700HV or 800HV.

In the present application, the performance of the polymer ceramic layer 10 is detected by using a falling ball impact test, wherein the falling ball is a 32 g stainless steel ball, and the thickness of the polymer ceramic layer 10 is 0.8 mm. In one embodiment, the polymer ceramic layer 10 is supported on the jig, wherein the surrounding edges of the polymer ceramic layer 10 are supported by 5 mm, and the middle part is suspended; 32 g of stainless steel balls are freely dropped from a certain height to the polymer to be tested. For the point to be detected on the surface of the ceramic layer 10, record the height at which the polymer ceramic layer 10 is broken as the falling ball height. Further, a 32g stainless steel ball was freely dropped from a certain height to the center of the surface of the polymer ceramic layer 10 to be tested, and each height was tested 5 times, and the height at which the polymer ceramic layer 10 was broken was recorded as the falling ball height. In the embodiment of the present application, the falling ball height of the polymer ceramic layer 10 is greater than or equal to 70 cm. Further, the falling ball height of the polymer ceramic layer 10 is 70cm-100cm. Furthermore, the falling ball height of the polymer ceramic layer 10 is 80cm-95cm. In this application, the polymer ceramic layer 10 has excellent drop resistance and strong toughness.

In this application, the four-point bending strength of the polymer ceramic layer 10 is detected by adopting the GB/T 6569-2006 standard. In the embodiment of the present application, the four-point bending strength of the polymer ceramic layer 10 is greater than or equal to 400N. Further, the four-point bending strength of the polymer ceramic layer 10 is 400N-800N. Furthermore, the Vickers hardness of the polymer ceramic layer 10 is 500N-750N. Specifically, the four-point bending strength of the polymer ceramic layer 10 may be, but not limited to, 400N, 450N, 500N, 600N, 650N, 700N or 750N.

In this application, the polymer ceramic layer 10 is placed on the extrusion fixture, and the top of the spherical anti-compression head with a diameter of 10 mm is aligned with the middle position of the polymer ceramic layer 10, and the polymer ceramic layer 10 is pressed at a compression speed of 5 mm/min. The ceramic layer 10 is pressed until the polymer ceramic layer 10 is broken, and the peak pressure at this time is recorded as the extrusion force. In the embodiment of the present application, the extrusion force of the polymer ceramic layer 10 is greater than or equal to 500N. Further, the extrusion force of the polymer ceramic layer 10 is 500N-700N. Furthermore, the extrusion force of the polymer ceramic layer 10 is 550N-650N. Specifically, the extrusion force of the polymer ceramic layer 10 may be, but not limited to, 500N, 550N, 570N, 600N, 650N, 680N or 700N.

In the embodiment of the present application, the polymer ceramic layer 10 may also have a colorant, so that the casing 100 has different color appearances and improves the visual effect. Specifically, the coloring agent can be but not limited to be selected from carbon black, iron oxide, cobalt oxide, cerium oxide, nickel oxide, bismuth oxide, zinc oxide, manganese oxide, chromium oxide, copper oxide, vanadium oxide and tin oxide at least one. In one embodiment, the mass content of the colorant in the polymer ceramic layer 10 is less than or equal to 15%, so as to improve the color of the polymer ceramic layer 10 without affecting the content of ceramic particles. Further, the mass content of the colorant in the polymer ceramic layer 10 is 0.5%-10%.

Please refer to FIG. 5 , which is a schematic structural diagram of a housing provided in another embodiment of the present application. The housing 100 may further include a protective layer 20 disposed on the surface of the polymer ceramic layer 10 . The casing 100 has an inner surface and an outer surface oppositely disposed during use, and the protective layer 20 is located on one side of the outer surface, so as to play a protective role in the use of the casing 100 . Specifically, the protective layer 20 may be, but not limited to, an anti-fingerprint layer, a hardened layer, and the like. Specifically, the thickness of the protection layer 20 may be, but not limited to, 0.5 μm-3 μm. In one embodiment, the protection layer 20 includes an anti-fingerprint layer. Optionally, the contact angle of the anti-fingerprint layer is greater than 105°. The contact angle is an important parameter to measure the wettability of the liquid on the surface of the material. The contact angle of the anti-fingerprint layer is greater than 105°, indicating that the liquid is easy to move on the anti-fingerprint layer, thereby avoiding pollution to its surface, and has excellent anti-fingerprint properties. performance. Optionally, the anti-fingerprint layer includes fluorine-containing compounds. Specifically, the fluorine-containing compound may be, but not limited to, fluorosilicon polymer, perfluoropolyether, fluorine-containing acrylate, and the like. Further, the anti-fingerprint layer also includes silicon dioxide, and the friction resistance of the anti-fingerprint layer is further improved by adding silicon dioxide. In another embodiment, the protective layer 20 includes a hardened layer. The surface hardness and scratch resistance of the casing 100 are further improved by providing a hardened layer. Optionally, the material of the hardened layer includes at least one of graphite, aluminum oxide, zirconium oxide, silicon oxide, chromium nitride and titanium nitride.

In this application, the thickness of the housing 100 can be selected according to the needs of its application scenarios, which is not limited; in one embodiment, the housing 100 can be used as the shell, middle frame, decoration, etc. of the electronic device 200, such as As the casing of mobile phones, tablet computers, notebook computers, watches, MP3, MP4, GPS navigators, digital cameras, etc. The casing 100 in the embodiment of the present application may have a 2D structure, a 2.5D structure, a 3D structure, etc., which may be selected according to needs. In an embodiment, when the casing 100 is used as a mobile phone back cover, the thickness of the casing 100 is 0.5mm-1.2mm. Specifically, the thickness of the housing 100 may be, but not limited to, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm or 1.2mm. In another embodiment, when the case 100 is used as the back cover of a mobile phone, the case 100 includes a main body and an extension portion disposed on the edge of the main body, and the extension is bent toward the main body; at this time, the case 100 is curved.

In the embodiment of the present application, the surface roughness of the casing 100 is less than 0.1 μm. By providing the casing 100 with a small surface roughness, it is beneficial to enhance its ceramic texture and enhance the visual effect. Further, the surface roughness of the casing 100 is 0.02 μm-0.08 μm. In the embodiment of the present application, the density of the housing 100 is less than or equal to 2.6 g/cm ³ . Further, the density of the casing 100 is 2.3g/cm ³ -2.6g/cm ³ . The casing 100 provided by the present application has a low density, which is beneficial to meet the development demand of lightness and thinness.

The preparation method of the casing provided by the implementation of the present application and the performance of the obtained casing will be further described below through specific examples and comparative examples.

Example 1

A method for preparing a casing, comprising:

Spherical zinc oxide with a particle size of 100nm-150nm and spherical alumina with a particle size of 100-200nm are mixed at a mass ratio of 10:1; 20kg of composite ceramic particles, silane coupling agent accounting for 1% of the mass of the composite ceramic particles, The polyvinyl alcohol accounting for 0.5% of the mass of the composite ceramic particles and the carbon black accounting for 2% of the mass of the composite ceramic particles are mixed to obtain a mixed material; water and alumina grinding beads are added to the mixed material, wherein the mass ratio of the mixed material, water and ball milling beads is 1 :2:0.5, and placed in a ball mill tank for ball milling and dispersion for 48 hours to obtain a mixed slurry. The mixed slurry is spray-dried and granulated to obtain the treated ceramic particles, wherein the feed temperature is 80°C, the inlet air temperature is 150°C, the exhaust air temperature is 80°C, the temperature inside the tower is 85°C, and the negative pressure inside the tower is is 100pa. Mix the treated ceramic particles with the polymer at a mass ratio of 8:2 to form a mixture, and the polymer includes polyphenylene sulfide and polyphenylene sulfone; the mixture is placed in a blending extruder and blended 3 times, It is then extruded and pelletized to obtain injection molding feed. The injection molding feed was dried at 120°C for 12 hours, and then injected into the injection machine for injection molding; the molding temperature was 345°C, the injection speed was 90%, the injection pressure was 200MPa, the mold temperature was 145°C, and the holding time was 30s. A polymer ceramic body is obtained.

Mix melamine and zinc in a mass ratio of 6:4, add ethanol, ammonium stearate and polyvinyl alcohol, and stir for 6 hours to obtain a pretreatment liquid, wherein the mass content of the accelerator in the pretreatment liquid is 40%, and the amount of ethanol The mass content is 55%, the mass content of ammonium stearate is 1%, and the mass content of polyvinyl alcohol is 1%. The pretreatment liquid is evenly coated on the polymer ceramic body by means of coating, and dried at 80° C. to form a pretreatment layer to obtain a composite body.

Put the composite green body in the jig, and then put them together in the oven for heat treatment according to the following curve: room temperature rises to 250°C for 1h, keeps at 250°C for 1h; heats up from 250°C to 330°C for 1h, keeps at 330°C for 2h, then The first green body was obtained by natural cooling. Put the first green body in a hot-pressing sintering furnace for hot-pressing. The hot-pressing temperature is 360°C, the holding time is 4h, the hot-pressing pressure is 40MPa, and the hot-pressing atmosphere is nitrogen. After the hot-pressing is completed, the temperature is naturally lowered to obtain the first Two body.

Carry out CNC machining on the second green body according to the product drawings. PCD milling cutter is used for CNC machining, the spindle speed is 22000rpm, and the single cutting amount is 50μm; then rough polishing is carried out with a sweeping machine, and the polishing disc is made of pig hair combined with microdermabrasion Material, rough polishing liquid is water system diamond polishing liquid, the particle size of diamond micropowder in the rough polishing liquid is 2 μm, the concentration of rough polishing liquid is 10wt%; The particle size of the silicon is 200nm, and the concentration of the fine polishing liquid is 40wt%, so that the pretreatment layer is removed, a polymer ceramic layer is obtained, and the casing is obtained.

Example 2

Roughly the same as Example 1, the difference is that after the polymer ceramic layer is prepared, a hardened layer is coated on the surface of the polymer ceramic layer by evaporation coating, the material of the hardened layer is alumina, and the thickness of the hardened layer is 1 μm, and then plate an anti-fingerprint layer on the surface of the hardened layer to make a shell.

Comparative example 1

A zirconia ceramic shell is formed by sintering a zirconia ceramic green body.

Comparative example 2

The casing is prepared according to the method shown in Example 1 of the patent CN108483991A.

Comparative example 3

It is roughly the same as in Example 1, except that the polymer ceramic body is directly heat-treated without spraying the pretreatment liquid.

Comparative example 4

Roughly the same as Comparative Example 3, the difference is that the heat treatment process includes heating from room temperature to 250°C for 1 hour, holding at 250°C for 24 hours; heating from 250°C to 330°C for 1 hour, and holding at 330°C for 24 hours.

Performance testing

According to the detection method recorded in the description, the casings prepared in the examples and comparative examples were tested for pencil hardness, Vickers hardness, falling ball height, four-point bending strength, extrusion force and density, and the results are shown in Table 1 , wherein the thicknesses of the shells made in the examples and the comparative examples in each test are consistent.

Table 1 performance test results

The embodiments of the present application provide a casing with high pencil hardness and Vickers hardness, excellent scratch resistance, high ball drop height, high four-point bending strength, strong extrusion force, excellent toughness and strength, and overall low density. Compared with Comparative Example 1, the overall toughness of the shell provided by the embodiment of the present application is improved, and the density is reduced; compared with Comparative Examples 2-4, the surface hardness and overall strength of the shell provided by the embodiment of the present application are greatly improved, and it is more conducive to its application.

The present application also provides an electronic device 200, including the casing 100 in any one of the above-mentioned implementation manners. It can be understood that the electronic device 200 may be, but not limited to, a mobile phone, a tablet computer, a notebook computer, a watch, an MP3, an MP4, a GPS navigator, a digital camera, and the like. Please refer to FIG. 6 , which is a schematic structural diagram of an electronic device provided in an embodiment of the present application, wherein the electronic device 200 includes a casing 100 . The casing 100 can improve the strength and surface hardness of the electronic device 200, and the electronic device 200 has a ceramic texture appearance, which has excellent product competitiveness. Please refer to FIG. 7, which is a schematic diagram of the structure and composition of an electronic device provided in an embodiment of the present application. The structure of the electronic device 200 may include an RF circuit 210, a memory 220, an input unit 230, a display unit 240, a sensor 250, an audio circuit 260, a WiFi Module 270, processor 280, power supply 290 and so on. Wherein, RF circuit 210 , memory 220 , input unit 230 , display unit 240 , sensor 250 , audio circuit 260 , and WiFi module 270 are respectively connected to processor 280 ; power supply 290 is used to provide electric energy for the entire electronic device 200 . Specifically, the RF circuit 210 is used for sending and receiving signals; the memory 220 is used for storing data instruction information; the input unit 230 is used for inputting information, and may specifically include other input devices such as a touch panel and operation buttons; the display unit 240 may include a display screen, etc.; sensor 250 includes an infrared sensor, a laser sensor, etc., and is used to detect user approach signals, distance signals, etc.; speaker 261 and microphone 262 are connected to processor 280 through audio circuit 260, and are used to receive and send sound signals; WiFi module 270 It is used to receive and transmit WiFi signals; the processor 280 is used to process data information of the electronic device 200 .

The content provided by the embodiment of the application has been introduced in detail above, and the principle and implementation of the application have been elaborated and explained, but the above description is only used to help understand the method of the application and its core idea; at the same time, for this field Those of ordinary skill in the art will have changes in specific implementation methods and application scopes based on the ideas of the present application. To sum up, the contents of this specification should not be understood as limiting the application.

Claims (13)

1. A preparation method for a shell, characterized in that, comprising: Coating and/or immersing the polymer ceramic body in a pretreatment liquid, forming a pretreatment layer on the surface of the polymer ceramic body after drying, to obtain a composite body, wherein the polymer ceramic body includes polymer , the pretreatment liquid includes an accelerator capable of promoting crosslinking of the polymer; After the composite green body is heat-treated and hot-pressed, the pre-treatment layer is removed to obtain a polymer ceramic layer and a casing. 2. The preparation method according to claim 1, characterized in that, the mass content of the accelerator in the pretreatment liquid is 10%-50%. 3. preparation method as claimed in claim 1, is characterized in that, described accelerator comprises at least one in organic accelerator and metal accelerator; The organic accelerator includes at least one of melamine, hexamethoxymethyl melamine, trihydroxybenzene, pentaerythritol triallyl ether, phenol and hindered phenols, and the metal accelerator includes silver, copper, iron, lead, at least one of zinc and magnesium. 4. The preparation method according to claim 3, characterized in that, the mass ratio of the organic accelerator and the metal accelerator in the accelerator is 1.2-4. 5. preparation method as claimed in claim 1 is characterized in that, described pretreatment liquid also comprises dispersant, binding agent and solvent, and the mass content of described dispersant in described pretreatment liquid is 0.5%-5% %, the mass content of the binder is 1%-5%, and the mass content of the solvent is 50%-80%; The dispersant includes at least one of silane coupling agent, stearic acid, ammonium stearate and polyethylene glycol, and the binder includes polyvinyl alcohol, polyvinyl butyral ester, polyethylene glycol At least one of alcohol and acrylic resin, the solvent includes at least one of water, ethanol and acetone. 6. The preparation method according to claim 1, characterized in that, the time of the heat treatment is less than or equal to 12h. 7. The preparation method according to claim 6, characterized in that, the heat treatment includes heating from 15°C-40°C to 220°C-280°C within 0.5h-1h and then keeping it warm for 0.5h-2h, and then -Raising the temperature from 220°C-280°C to 300°C-380°C within 1 hour and then keeping it warm for 0.5h-4h; the temperature of the heat treatment is higher than the melting temperature of the polymer and lower than the decomposition temperature of the polymer. 8. The preparation method according to claim 1, characterized in that, the coating and/or soaking includes treatment at 15°C-40°C for 1h-2h, the drying temperature is 80°C-100°C, the The thickness of the pretreatment layer is 10 μm-100 μm. 9. The preparation method according to claim 1, characterized in that, the hot pressing includes treating at 20MPa-80MPa, 300°C-400°C for 2h-12h, and the temperature of the hot pressing is higher than that of the polymer glass transition temperature and less than the decomposition temperature of the polymer. 10. The preparation method according to claim 1, wherein the preparation of the polymer ceramic body comprises: After the ceramic particles are mixed with the polymer, the injection molding feed is obtained through granulation; The injection molding feed is injected to obtain a polymer ceramic green body. 11. A housing, characterized in that it is manufactured by the preparation method according to any one of claims 1-10, and the housing comprises a polymer ceramic layer. 12. The casing according to claim 11, wherein in the polymer ceramic layer, the polymer is cross-linked to form a network structure, and the ceramic particles are dispersed in the network structure; The polymer ceramic layer includes ceramic particles and polymers, the ceramic particles include at least one of zinc oxide, zirconium oxide, aluminum oxide, silicon dioxide, titanium oxide and silicon carbide, and the diameter of the ceramic particles is 20nm -1 μm, the polymer includes at least one of polyphenylene sulfide, polyphenylene sulfone, polyamide and ethylene-vinyl acetate copolymer. 13. An electronic device, comprising the casing according to any one of claims 11-12.

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